EP0310689A1 - Process for the preparation of 1,4-diazabicyclo(2,2,2)-octanes - Google Patents

Abstract

1,4-Diazabicyclo[2.2.2]octane and C-substituted 1,4- diazabicyclo[2.2.2]octanes of the formula (I) <IMAGE> in which R<1> and R<2> can denote hydrogen, alkyl having 1 to 4 carbon atoms or alkenyl radicals having 1 to 4 carbon atoms, are prepared from heterocyclic amines of the formula (II) <IMAGE> in which R<1> and R<2> have the above meaning and R<3> denotes hydrogen or hydroxyethyl or aminoethyl and X denotes hydroxyl, amino, hydroxyethyl or aminoethyl radicals, in the presence of borosilicate and/or iron silicate zeolites as catalysts. Particularly suitable catalysts are the borosilicate and iron silicate zeolites of the pentasil type.

Description

The present invention relates to a process for the preparation of 1,4-diazabicyclo (2,2,2) octane (DABCO) and its C-substituted derivatives by reacting heterocyclic amines in the presence of borosilicate and / or iron silicate zeolites as catalysts.

It is known that DABCO and its derivatives can be prepared heterogeneously catalyzed from heterocyclic amines. So far, the phosphates of Ca, Sr, Ba, Zn, La, Al, Co, Ni, Ce have been used as catalysts, but unsatisfactory yields have been achieved.

It is also known to use aluminosilicate zeolites of the ZSM type as heterogeneous catalysts for this reaction (EP 158 319). The yields are small; with low sales, high selectivities are found, but with high sales, low selectivities are found. The reaction product also has a number of undesirable by-products such as N-alkylpiperazines and pyrazine derivatives. The by-products have physical and chemical properties similar to DABCO and are therefore difficult to separate using conventional physical methods such as distillation and crystallization. The purity of the DABCO is subject to high requirements for further processing and therefore requires extensive cleaning.

The task was therefore to find catalysts which give high yields (conversion x selectivity) of the desired 1,4-diazabicyclo (2,2,2) octanes and avoid the disadvantages mentioned above.

in der R¹ und R² Wasserstoff-, Alkyl- mit 1 bis 4 C-Atomen oder Alkenylreste mit 1 bis 4 C-Atomen bedeuten, in gewünschter Weise erhält, wenn man heterocyclische Amine der Formel (II)

in der R¹ und R² obige Bedeutung haben und R³ Wasserstoff- oder Hydroxyethyl- oder Aminoethyl- und X Hydroxyl-, Amino-, Hydroxyethyl- oder Aminoethylreste bedeuten, in Gegenwart von Boro- und/oder Eisensilikatzeolithen als Katalysatoren umsetzt.It was found that 1,4-diazabicyclo (2,2,2) octane and C-substituted 1,4-diazabicyclo (2,2,2) octanes of the formula (I)

in which R¹ and R² are hydrogen, alkyl having 1 to 4 carbon atoms or alkenyl radicals having 1 to 4 carbon atoms, are obtained in a desired manner if heterocyclic amines of the formula (II)

in which R¹ and R² have the above meaning and R³ are hydrogen or hydroxyethyl or aminoethyl and X are hydroxyl, amino, hydroxyethyl or aminoethyl radicals, in the presence of borosilicate and / or iron silicate zeolites as catalysts.

According to the invention, compounds such as e.g. Monohydroxyethylpiperazin, Dihydroxyethylpiperazin, Monoaminoethylpiperazin, Aminoethylhydroxyethylpiperazin be implemented.

The zeolites are advantageously used in the acidic form as catalysts for the process according to the invention. Zeolites are crystalline aluminum silicates that have a highly ordered structure with a rigid three-dimensional network of SiO₄ and AlO₄ tetrahedra, which are connected by common oxygen atoms. The ratio of the Si and Al atoms to oxygen is 1: 2. The electrovalence of the tetrahedra containing aluminum can be determined by including cations in the crystal, e.g. of an alkali or hydrogen ion balanced. A cation exchange is possible. The spaces between the tetrahedra are occupied by drying or calcining water molecules before dehydration.

In the zeolite, other elements such as B, Ga, Fe, Cr, V, As, Sb, Bi or Be or mixtures thereof can be built into the lattice instead of aluminum, or the silicon can be replaced by a tetravalent element such as Ge, Ti, Zr, Hf to be replaced.

These zeolites can have different chemical compositions. These are alumino, boro, iron, beryllium, gallium, chromium, arsenic, antimony and bismuth silicate zeolite or their mixtures as well as alumino, boro, gallium and iron germanate zeolites or their mixtures.

The borosilicate and iron silicate zeolites of the pentasil type are particularly suitable for the process according to the invention.

Borosilicate zeolites can be synthesized, for example, at 90 to 200 ° C under autogenous pressure by a boron compound, for example H₃BO₃, with a silicon compound, preferably highly disperse silicon dioxide in aqueous Amine solution, in particular in 1,6-hexanediamine or 1,3-propanediamine or triethylenetetramine solution with and in particular without addition of alkali or alkaline earth metal to the reaction. These also include the isotactic zeolites according to EP 34 727 and EP 46 504. Such borosilicate zeolites can also be prepared if the reaction is carried out in ethereal solution, for example diethylene glycol dimethyl ether or in alcoholic solution, for example 1,6-hexanediol, instead of in aqueous amine solution.

The iron silicate zeolite is obtained e.g. from an iron compound, preferably Fe₂ (SO₄) ₃ and a silicon compound, preferably highly disperse silicon dioxide in aqueous amine solution, in particular 1,6-hexanediamine, with or without addition of alkali metal or alkaline earth metal at 100 to 200 ° C. under autogenous pressure.

The borosilicate and iron silicate zeolites thus produced can, after their isolation, drying at 100 to 160 ° C, preferably 110 ° C and calcination at 450 to 550 ° C, preferably 500 ° C, with a binder in a ratio of 90: 10 to 40: 60 % By weight to be shaped into strands or tablets. Various aluminum oxides, preferably boehmite, amorphous aluminosilicates with an SiO₂ / Al₂O₃ ratio of 25:75 to 90: 5, preferably 75:25, silicon dioxide, preferably highly disperse SiO₂, mixtures of highly disperse SiO₂ and highly disperse Al₂O₃, TiO₂, ZrO₂ are suitable as binders as well as sound. After shaping, the extrudates or compacts are dried at 110 ° C / 16 h and calcined at 500 ° C / 16 h.

Advantageous catalysts are also obtained if the isolated iron or borosilicate zeolite is deformed directly after drying and is only subjected to calcination after the deformation. The iron and borosilicate zeolites produced can be used in pure form, without binders, as strands or tablets, with extrusion or peptizing aids, e.g. Ethyl cellulose, stearic acid, potato starch, formic acid, oxalic acid, acetic acid, nitric acid, ammonia, amines, silicon esters and graphite or mixtures thereof can be used.

Because of the way it is produced, the zeolite is not in the catalytically active, acidic H form, but is e.g. in the Na form, then this can be achieved by ion exchange, e.g. with ammonium ions and subsequent calcination or by treatment with acids completely or partially converted into the desired H form.

If a deactivation due to coke separation possibly occurs when using the zeolitic catalysts according to the invention, it is advisable to include the zeolites by burning off the coke deposit Air or with an air / N₂ mixture at 400 to 550 ° C, preferably 500 ° C to regenerate. This gives the zeolites their initial activity.

By partial coking (pre-coke) it is possible to adjust the activity of the catalyst for an optimal selectivity of the desired reaction product.

In order to achieve the highest possible selectivity, high sales and long service lives, it is advantageous to modify the zeolites. A suitable modification of the catalysts is e.g. in that the undeformed or deformed zeolite is doped with metal salts by ion exchange or by impregnation. As metals, alkali metals such as Li, Cs, K, alkaline earth metals such as Mg, Ca, Sr, metals of the 3rd, 4th and 5th main groups such as Al, Ga, Ge, Sn, Pb, Bi, transition metals of the 4th - 8th Subgroup such as Ti, Zr, V, Nb, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Sr, Ni, Pd, Pt, transition metals of the 1st and 2nd subgroup such as Cu, Ag , Zn, rare earth metals such as La, Ce, Pr, Nd, Er, Yb and U are used.

The doping is expediently carried out by placing the deformed zeolite in a riser tube and passing an aqueous or ammonial solution of a halide or a nitrate of the above-described metals at 20 to 100 ° C. Such an ion exchange can be carried out on the hydrogen, ammonium and alkali form of the zeolite. Another possibility of applying metal to the zeolite is by using the zeolitic material, e.g. impregnated with a halide, a nitrate or an oxide of the metals described above in aqueous, alcoholic or ammoniacal solution. Both an ion exchange and an impregnation are followed by at least one drying step, optionally a further calcination.

One possible embodiment is e.g. in that Cu (NO₃) ₂ x H₂O or Ni (NO₃) ₂ x 6 H₂O or Ce (NO₃) ₃ x 6 H₂O or La (NO₃) ₂ x 6 H₂O or Cs₂CO₃ is dissolved in water and the deformed or undeformed zeolite for a certain time, e.g. 30 minutes, soak. Any excess solution is freed of water in a rotary evaporator. The impregnated zeolite is then dried at approximately 150 ° C. and calcined at approximately 550 ° C. This impregnation process can be carried out several times in succession in order to set the desired metal content.

It is also possible to prepare an aqueous Ni (NO₃) ₂ solution or ammoniacal Pd (NO₃) ₂ solution and to slurry the pure powdered zeolite at 40 to 100 ° C. with stirring for about 24 hours. After filtering, drying at about 150 ° C and calcination at about 500 ° C it can obtained zeolitic material with or without binders can be processed into strands, pellets or eddy material.

Ion exchange of the zeolite present in the H form can be carried out by placing the zeolite in strands or pellets in a column and, for example, conducts an aqueous Ni (NO₃) ₂ solution or ammoniacal Pd (NO₃) ₂ solution at a slightly elevated temperature between 30 and 80 ° C in the circuit for 15 to 20 h. It is then washed out with water, dried at approximately 150 ° C. and calcined at approximately 550 ° C. Some metal doped zeolites, e.g. Pd-, Cu-, Ni-doped zeolites, an aftertreatment with hydrogen is advantageous.

Another possibility of modification consists in subjecting the zeolitic material - deformed or undeformed - to treatment with acids such as hydrochloric acid, hydrofluoric acid and phosphoric acid and / or water vapor. This is advantageous, e.g. so that zeolites in powder form are treated with 1N phosphoric acid at 80 ° C. for 1 hour. After the treatment, it is washed with water, dried at 110 ° C./16 hours and calcined at 500 ° C./20 hours. Another way of working is to treat zeolites with binders, e.g. 1 to 3 hours at temperatures of 60 to 80 ° C with a 3 to 25 wt .-%, in particular 12 to 20 wt .-% aqueous hydrochloric acid. The zeolite treated in this way is then washed with water, dried and calcined at 400 ° C. to 500 ° C.

A particular embodiment for the acid treatment consists in treating the zeolitic material with hydrofluoric acid, which is generally used as 0.001 n to 2 n, preferably 0.05 n to 0.5 n, of hydrofluoric acid, for example before it is preformed by heating under reflux for a period of generally 0.5 to 5, preferably 1 to 3 hours. After isolation, for example by filtering off and washing out the zeolitic material, it is expediently dried, for example at temperatures from 100 to 160 ° C., and calcined at temperatures of generally 450 ° C. to 600 ° C. According to a further preferred embodiment for the acid treatment, the zeolitic material is, after being deformed with a binder, at an elevated temperature, advantageously at from 50 to 90 ° C., preferably from 60 to 80 ° C., for a period of from 0.5 to 5, preferably treated with 12 to 20 wt .-% hydrochloric acid. The zeolitic material is then expediently washed out, dried at temperatures from 100 to 160 ° C. and calcined at temperatures from 450 to 600 ° C. HF treatment can also be followed by HCl treatment.

According to a different procedure, zeolites can be modified by applying phosphorus compounds, such as trimethoxy phosphate, trimethoxy phosphine, primary, secondary or tertiary sodium phosphate. Treatment with primary sodium phosphate has proven to be particularly advantageous. The zeolites are soaked in strand, tablet or fluidized form with aqueous NaH₂PO₄ solution, dried at 110 ° C and calcined at 500 ° C.

The catalysts can be used either as 2 to 4 mm strands or as tablets with 3 to 5 mm in diameter or as powders with particle sizes of 0.1 to 0.5 mm or as vortex contacts.

The conversion is preferred in the gas phase at 200 to 550 ° C, in particular 300 to 450 ° C, and a load WHSV = 0.1 to 20 h⁻¹, in particular 0.5 to 5 h⁻¹ (g starting material / g catalyst and hour). The reaction is carried out in a fixed bed or fluidized bed. In general, the conversion increases sharply with increasing temperature, while the selectivity decreases only slightly in a certain temperature range. The reaction can also be carried out in the liquid phase (suspension, trickle or bottoms procedure). The processes are generally carried out at normal pressure or elevated pressure and preferably continuously, but also batchwise.

Non-volatile or solid starting materials are in dissolved form, e.g. used in water, THF, toluene or petroleum ether solution. In general, dilution with solvents or inert gases such as N₂, Ar is also possible.

After the reaction, the resulting 1,4-diazabicyclo (2,2,2) octanes are processed by conventional methods, e.g. isolated from the reaction mixture by distillation; unreacted starting materials are optionally returned to the reaction.

Examples 1 to 8

The reaction is carried out under isothermal conditions in a tubular reactor (spiral 0.6 cm, 90 cm long) in the gas phase for at least 6 hours. The reaction products are separated and characterized by customary methods. The quantitative determination of the reaction products and the starting materials is carried out by gas chromatography.

The catalysts used in the examples are:

Catalyst A

A borosilicate zeolite of the pentasil type is in a hydrothermal synthesis from 640 g of highly disperse SiO₂, 122 g of H₃BO₃, 8 kg of an aqueous 1,6-hexanediamine solution (mixture 50: 50 wt.%) At 170 ° C under autogenous pressure in one Stirred autoclaves manufactured. After filtering off and washing out, the crystalline reaction product is dried at 100 ° C./24 h and calcined at 500 ° C./24 h. This borosilicate zeolite is composed of 94.2 wt.% SiO₂ and 2.3 wt.% B₂O₃.

This material is used to produce 2 mm strands by shaping with shaping aids, which are dried at 110 ° C./16 h and calcined at 500 ° C./24 h.

Catalyst B

An iron silicate zeolite of the pentasil type is dissolved under hydrothermal conditions at autogenous pressure and 165 ° C. from 273 g water glass, dissolved in 253 g of an aqueous 1,6-hexanediamine solution (mixture 50: 50% by weight) and 31 g iron sulfate, dissolved in 21 g of 96% sulfuric acid and 425 g of water were synthesized in a stirred autoclave for 4 days. The zeolite is filtered off, washed out, dried at 110 ° C./24 h and calcined at 500 ° C./24 h. An iron silicate zeolite with an SiO₂ / Fe₂O₃ ratio of 17.7 and an Na₂O content of 1.2% by weight is obtained. The catalyst is extruded with highly disperse SiO₂ in a weight ratio of 80:20 to 2.5 mm strands, dried at 110 ° C./16 h and calcined at 500 ° C./24 h.

Catalyst C

Catalyst C is obtained by impregnating catalyst A with a Pd (NO₃) ₂- / Ce (NO₃) ₃ solution. After drying at 130 ° C / 2 h and calcination at 540 ° C / 2 h, the Pd content is 1.3% by weight and the Ce content is 3.6% by weight.

Catalyst D

Catalyst D is obtained by deforming the borosilicate zeolite from catalyst A with highly disperse SiO₂ in a weight ratio of 70:30 to 2 mm strands, drying at 110 ° C./16 h and calcining at 500 ° C./16 h. These strands are impregnated with an aqueous NaH₂PO₄ solution, dried at 110 ° C and calcined at 500 ° C / 14 h. The Na content is 5% by weight and the P content is 7.5% by weight.

Catalyst E (comparative catalyst)

An aluminosilicate zeolite ZSM 5 is synthesized according to US Pat. No. 3,702,886, Example 1. This ZSM 5 zeolite is shaped with boehmite in a weight ratio of 60:40, dried at 110 ° C. and calcined at 500 ° C. for 16 hours. The strands are ion-exchanged with 20% NH₄Cl solution at 80 ° C / 2 h using the usual method until the Na content is 0.02% by weight (after drying at 110 ° C and calcination at 500 ° C / 5 h) .

The test results achieved with the catalysts described above are listed in Table 1 below.

Working solution I: monohydroxyethylpiperazine dissolved in water 25 g: 75 g. Working solution II: mixture of mono- and dihydroxyethylpiperazine (weight ratio 20:80) dissolved in water 25 g: 75 g.

Table 1 example 1 2nd 3rd 4th 5 * 6 Operational solution I. I. I. I. I. II catalyst A B C. D E A temperature 400 ° C 400 ° C 400 ° C 400 ° C 400 ° C 400 ° C WHSV 1.5 h⁻¹ 1.5 h⁻¹ 1.5 h⁻¹ 3 h⁻¹ 2 h⁻¹ 1.5 h⁻¹ Sales % 98.9 99.7 99.7 99.9 99.6 99.8 Selectivity% DABCO 65.6 73.5 76.8 83.2 68.5 68.3 Piperazine 7.3 10.3 5.9 9.9 12.4 9.4 * Comparative example Table 1 - Continued example 7 8th Operational solution II II catalyst C. D temperature 400 ° C 400 ° C WHSV 2 h⁻¹ 2 h⁻¹ Sales % 99.6 99.8 Selectivity% DABCO 67.8 84.9 Piperazine 6.5 3.9 * Comparative example

Claims (5)

1. Process for the preparation of 1,4-diazabicyclo (2,2,2) octane and C-substituted 1,4-diazabicyclo (2,2,2) octanes of the formula (I)

in which R¹ and R² can be hydrogen, alkyl having 1 to 4 carbon atoms or alkenyl radicals having 1 to 4 carbon atoms, characterized in that heterocyclic amines of the formula (II)

in which R¹ and R² have the above meaning and R³ are hydrogen or hydroxyethyl or aminoethyl and X are hydroxyl, amino, hydroxyethyl or aminoethyl radicals, in the presence of borosilicate and / or iron silicate zeolites as catalysts. 2. The method according to claim 1, characterized in that reacting monohydroxyethylpiperazine or dihydroxyethylpiperazine or mixtures thereof as starting materials. 3. Process according to claims 1 and 2, characterized in that zeolites of the pentasil type are used as catalysts. 4. Process according to claims 1 to 3, characterized in that borosilicate zeolites of the pentasil type are used as catalysts. 5. Process according to claims 1 to 4, characterized in that modified borosilicate and / or iron silicate zeolites are used as catalysts with rare earths and / or transition metals and / or alkali and / or alkaline earth metals and / or phosphorus compounds.